1. Field of the Invention
The present invention relates to the field of applying non-ablative electromagnetic radiation to enhance wound healing during the early stages of wound development and to inhibit the progression of wounds to later stages.
2. Information Disclosure Statement
The development of wounds can be divided into four major stages. In Stage One, the skin will be warm, pink or reddened, and usually inflamed. In this stage, though the skin may look irritated, it will still be intact. In Stage Two, there is noticeable skin breakdown that is superficial in nature. At this stage, the wound may look like a blister or abrasion. In Stage Three, there is observed full thickness skin loss into the subcutaneous tissue. Finally, Stage Four represents full thickness damage to the underlying tissue, muscle, or tendons.
Current wound healing and wound debridement techniques focus exclusively on the healing of stage 3 and late stage 2 wounds, where there is true environmental exposure of subcutaneous tissue. Such wounds appear primarily as open wounds, or at a minimum appear as blisters or abrasions. There have not yet been efforts to heal wounds at their earliest stages, before such wounds mature into ulcers or other open wounds.
Low level laser therapy (LLLT), or the use of lasers of a lower power, is a technique currently used to promote wound healing. Such techniques target stage 3 and 4 wounds which are generally characterized as open wounds, blisters and ulcers. All LLLT techniques use radiation with powers of less than 1 Watt, and are generally in the range of 250 mW. LLLT devices typically deliver 10 mW–200 mW of power during treatment. LLLT treatments typically deliver power densities ranging from 0.05 W/Cm2–5 W/cm2 and energy densities ranging from 0.5–10 J/cm2. This technique utilizes a process for wound healing known as photonic biostimulation. It is claimed that exposing an open wound to visible and infrared radiation produces observable reductions in the amount of time needed for healing.
For example, this healing stimulation technique is described in U.S. Pat. No. 5,766,233 by Thiberg, which utilizes a light-emitting diode array to deliver infrared radiation and visible red light. Pulsed infrared radiation is emitted by a large array of individual low power diodes that emit a combined total power of 900 mW over 3 minutes, followed by pulsed visible red light emitted by individual low power diodes that together produce a combined total intensity of about 3000 millicandela, with an associated power of approximately 900 mW, over 3 minutes. This invention emphasizes the need to irradiate the treatment site with both visible and infrared radiation. Furthermore, the array of low power diodes creates a beam size with a large surface area, which results in a low power density.
U.S. Pat. No. 5,259,380, by Mendes et al., discloses a low power therapy system consisting of a focused array of light-emitting diodes. It specifically discloses an array for emitting red light for wound healing with a power density on the order of 15 mW/cm2, utilizing powers between 2 and 10 mW and treatment times ranging from 7 to 20 minutes.
Another example is U.S. Pat. No. 6,267,779, which discloses an apparatus for biostimulation and treatment of tissue consisting of two focusable laser treatment wands for the continuous or pulsed emission of coincident infrared and visible radiation. Embodiments include application of laser radiation with wavelengths ranging from 400 to 700 nm and from 900 to 1100 nm. The power range runs from 0–2 W, specifying an energy of 1–99 J over treatment times ranging from 1–60 minutes. The patent claims that the intersection of the beams in the patient's body has an increased therapeutic effect.
U.S. Pat. No. 5,445,146 discloses a method for pain reduction and healing using a low level laser system with power between 100 and 800 mW with an energy density limited to the range of 1–15 J/cm2.
There are many LLLT techniques for use in a variety of medical applications, but there is currently no actual proof of low level laser therapy's usefulness in stimulating tissue repair and wound healing. Though LLLT applications deliver a variety of energy densities, they often deliver the energy over long periods of time using lower radiation powers, which may be responsible for their lack of proven effectiveness.
As an alternative to LLLT, it has been shown that irradiation of an open wound with a 980 nm laser at powers of at least 5 Watts, continuously applied for a period between 10 seconds and 20 minutes or greater, is an effective method of stimulating the healing of open wounds. In a specific example disclosed in that invention, the energy density applied to a wound was approximately 33 J/cm2. See U.S. Pat. No. 6,165,205.
The present invention is unique among both low level laser therapy and other radiation treatments, in that said therapies and techniques are utilized to encourage healing exclusively in open wounds. They are not primarily applied to a wound as a preventative measure, but are used after a wound has progressed to a level where there is typically a significant breach of the skin and exposure of subcutaneous tissue to the outside environment.
Radiation treatment has also been utilized as a preventive treatment, though not directly for wound healing. U.S. Pat. No. 6,210,426 discloses a method for scar prevention following surgical procedures. A handpiece applies optical radiation to the incision 2 days to 2 months after surgery. Wavelengths between 530 and 1000 nm with energy densities ranging from 2–12 J/cm2 are used. This treatment is used to prevent the build up of scar tissue as a wound heals, but does not enhance the healing process itself.
Psoriasis and eczema are two skin conditions that often occur as Stage One or Stage Two wounds. Psoriasis is defined as a common, scaly dermatosis characterized by red and raised patches of skin. It is thought that psoriasis is caused by an overproduction of new skin cells which rise to the surface of the skin before old skin cells die and are sluffed off. This results in a break in the stratum corneum, exposing living skin cells to the environment. In early stages, psoriasis occurs as small red bumps, which can later progress to scales. Such bumps or scales can open after scratching or other irritation that can aggravate the condition and result in open wounds. There is currently no cure for psoriasis.
Eczema is defined as an itchy dermatosis caused by a variety of factors, and is characterized by a redness of the skin due to an overconcentration of capillaries, oedema (the presence of abnormally large amounts of fluid in the intercellular tissue spaces of the skin), and crusting or scaling of the skin in more chronic cases. Later stages of the disease, or scratching by the patient, can result in skin that is broken, raw or bleeding.
Methods are known for treating psoriasis and eczema, though these methods are concerned with treating open wounds or sores associated with these conditions. Included among these methods is treatment of psoriasis with electromagnetic radiation. Talmore, in U.S. Pat. No. 5,344,433, describes a method for treating “psoriasis skin wounds” with high intensity ultraviolet and infrared radiation, produced by a lamp, focused with a lens, and delivered through a liquid light guide with a minimum irradiance of 1 mW/cm2.
There is a need for a method to treat wounds at their earliest stages, including early stages of eczema and psoriasis, and stimulate healing before such wounds progress into larger or deeper wounds. In particular, a method for healing psoriasis while it is still in its early stages (when symptoms are limited to red bumps or scales, and are not yet open sores) would be extremely useful in stopping the spread of psoriasis to other parts of the body. The present invention fills this need.